I have never bow hunted before and was wanting to know how do you go about choosing the right bow?

I have seen two companys that im really intrested in and that is hoyt and matthews. I was on ebay and some guy was selling his bow because the draw length was to long. What is the draw length and how can you figure this out. Just remember i have no clue about any archery stuff so please give full explainitons. I would like to know what all you look for when buying a bow. Thanks for your time on this manner.